Epidermal growth factor and interleukin-1β utilize divergent signaling pathways to synergistically upregulate cyclooxygenase-2 gene expression in human amnion-derived WISH cells

• Published in: Biology of reproduction Vol. 71; no. 6; pp. 2079 - 2086
• Main Authors: ACKERMAN, William E, ROVIN, Brad H, KNISS, Douglas A
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.12.2004
• Subjects: Biological and medical sciences; Embryology: invertebrates and vertebrates. Teratology; Fetal membranes; Fundamental and applied biological sciences. Psychology; General aspects. Development. Fetal membranes; Vertebrates: reproduction; Human; Signal transduction; Reproduction; Epidermal growth factor; Fetal membrane; Enzyme; Cyclooxygenase 2; Cytokine; Amnion; Interleukin 1β; Oxidoreductases; Gene expression
• DOI: 10.1095/biolreprod.104.030841
• ISSN: 0006-3363

In human parturition, uterotonic prostaglandins (PGs) arise predominantly via increased expression of cyclooxygenase-2 (COX-2 [also known as prostaglandin synthase 2]) within intrauterine tissues. Interleukin-1 (IL-1) and epidermal growth factor (EGF), both inducers of COX-2 transcription, are among numerous factors that accumulate within amniotic fluid with advancing gestation. It was previously demonstrated that EGF could potentiate IL-1 beta -driven PGE2 production in amnion and amnion-derived (WISH) cells. To define the mechanism for this observation, we hypothesized that EGF and IL-1 beta might exhibit synergism in regulating COX-2 gene expression. In WISH cells, combined treatment with EGF and IL-1 beta resulted in a greater-than-additive increase in COX-2 mRNA relative to challenge with either agent independently. Augmentation of IL-1 beta -induced transactivation by EGF was not observed in cells harboring reporter plasmids bearing nuclear factor-kappa B (NF Kappa B) regulatory elements alone, but was evident when a fragment (-891/ +9) of the COX-2 gene 5'-promoter was present. Both agents transiently activated intermediates of multiple signaling pathways potentially involved in the regulation of COX-2 gene expression. The 26 S proteasome inhibitor, MG-132, selectively abrogated IL-1 beta -driven NF Kappa B activation and COX-2 mRNA expression. Only pharmacologic blockade of the p38 mitogen-activated protein kinase eliminated COX-2 expression following EGF stimulation. We conclude that EGF and IL-1 beta appear to signal through different signaling cascades leading to COX-2 gene expression. IL-1 beta employs the NF Kappa B pathway predominantly, while the spectrum of EGF signaling is broader and includes p38 kinase. The synergism observed between IL-1 beta and EGF does not rely on augmented NF Kappa B function, but rather, occurs through differential use of independent response elements within the COX-2 promoter.